A train at rest emits a sound at a frequency of 979 Hz. An observer in a car travels away
from the sound source at a speed of 36.3 m/s.
What is the frequency heard by the observer? Assume the speed of sound in air to
be 342 m/s.
Answer in units of Hz.

During the experiment if you could triple the breakaway magnetic force with all other quantities left unchanged, what is the new value for the critical velocity if it was v0 (initial velocity), initially? (b) now if you halved the radius with all other quantities left unchanged, what is the new critical velocity if it was v0 (initial velocity), initially? (c) if during the experiment, critical velocity quadrupled with all other quantities left unchanged, what is the new breakaway force if its magnitude was initially f0,?